Moderate

Sarcoid

Sarcoid is a bovine papillomavirus-associated skin tumour — the most common skin tumour in horses. It can look like a lump, a warty growth, a flat scaly patch, or an ulcerated sore, often on the head, groin, chest, or at an old wound. A photograph cannot diagnose sarcoid. Diagnosis is a vet exam and usually a biopsy. The skin scan is a first look at the lump or patch, not a verdict that your horse has sarcoid, and there is no sarcoid scanner.

Symptoms to watch for

A firm lump, warty growth, or raised nodule on the skin

A flat, scaly, or hairless patch that does not behave like rain rot or sweet itch

A growth at an old wound, a girth or tack site, or on the head, groin, chest, or belly

A lump that slowly enlarges, ulcerates, or bleeds after being knocked or rubbed

More than one lump or patch, or a lesion that looks like proud flesh or a wart but does not settle

Some sarcoids stay small for a long time; a change in size or surface is a reason to book a vet, not a photo verdict

Common causes

Bovine papillomavirus (BPV) associated with the tumour — not the same condition as rain rot, sweet itch, or mud fever
A lump or patch at an old wound, a fly-bitten site, or where tack rubs — location is a clue, not a diagnosis
Individual susceptibility; some horses grow more than one sarcoid over time
Trauma, picking, or rubbing that can turn a quiet patch into a larger, rawer growth
Not a simple wart in a young horse, and not a rain-rot scab — those can look similar and need a vet

Prevention

Watch lumps and patches, especially at old wounds and tack sites, and book a vet rather than waiting for a photo guess
Keep wounds clean and flies down — an open sore is a poor place for a new growth to start
Do not pick, ligate, burn, or 'treat' a lump from a web article or a scan result
Do not treat a photo, a lump, or a scan result as a diagnosis
Skin photos can help you and your vet track a lump or patch over time — they do not confirm or rule out sarcoid

What to do

1
Book a vet visit for any new lump or persistent patch. Diagnosis is a vet exam and usually a biopsy, not a photograph.
2
Photograph the lump or patch in good light and keep it on the horse's record so you and the vet can see change over time.
3
Do not cut, burn, freeze, ligate, or apply a cream from a photo guess — interference can make some sarcoids worse.
4
Use a skin scan only as a first look at the lump or patch to share, not as a sarcoid test. There is no sarcoid scanner.
5
If sarcoid is confirmed, follow the plan your vet prescribes — that may include biopsy, surgery, topical treatment, or referral. Do not start a treatment protocol from a photo.
6
Keep the vet on the same page. Share what you see; do not treat a photo as a verdict.

When to call the vet

Pick up the phone if…

Schedule a vet visit if you find a new lump, a warty growth, a flat scaly patch that does not settle, or a sore at an old wound or tack site. Call sooner if the lump is growing, ulcerating, bleeding, or interfering with the tack or the eye. A photograph cannot diagnose sarcoid. Diagnosis is a vet exam and usually a biopsy. The skin scan is a first look at the lump or patch, not a verdict, and there is no sarcoid scanner.